Manufacture of devices such as modern displays employ photo active adhesives to cure layers of glass and other items together to form the display stack. Curing of photo active adhesives may be performed with conventional LED devices, both on the front of the device as an ‘area’ cure and on the sides of the device as an ‘edge’ cure. Key to the edge cure process is emitting a high enough irradiance over a narrow target beam width line to avoid ‘over curing’ of sensitive items outside of the target region. An example target region has a desired line width less than 3 mm at a working distance of 10 mm.
Childers (U.S. Pat. No. 9,109,777) describes a light source with a linear array of light-emitting elements aligned with and emitting light through a cylindrical lens, wherein the cylindrical lens reduces an angular spread of light in a widthwise axis of the linear array.
The inventors herein have recognized potential issues with the above approach. Namely, conventional LED devices are Lambertian emitters, and emit radiation over a broad target region with angular content in all directions. The emitted light from conventional LED devices quickly spreads out in a widthwise direction beyond a narrow width target region, within small distances proximal to the LEDs. Furthermore, although passing the light emitted from Lambertian emitters through a cylindrical lens aids in focusing and reducing the widthwise dispersion of emitted light, the light emitted from the cylindrical lens diverges beyond the bounds of the narrow beam width target. Thus, over curing beyond a target region of sensitive work pieces may not be substantially reduced.
One approach that at least partially addresses the above issues includes an edge-curing device, comprising a cylindrical lens, a linear array of light-emitting elements, and an aperture, each aligned symmetrically about a longitudinal plane in a housing, wherein the cylindrical lens is positioned between the linear array of light-emitting elements and the aperture, the aperture spans the length of the cylindrical lens and is positioned directly adjacent to an emitting face of the cylindrical lens, and light emitted from the linear array of light-emitting elements and passing through the cylindrical lens is emitted from the emitting face and focused by the aperture within a beam width centered about the longitudinal plane.
In another embodiment, a method of edge curing a workpiece may comprise aligning longitudinal axes of each of a linear array of light-emitting elements, a cylindrical lens, and an aperture on a longitudinal plane, receiving light from the linear array of light-emitting elements at an incident face of the cylindrical lens, positioning the aperture directly adjacent to an emitting face of the cylindrical lens wherein light received at the incident face is collimated by the cylindrical lens and emitted at the emitting face, and focusing the emitted light by the aperture within a beam width centered about the longitudinal plane on to the workpiece positioned along the longitudinal plane at a working distance from the emitting face.
In another embodiment, an edge-curing system may comprise a housing, including a linear array of light-emitting elements, a cylindrical lens, and a cylindrical lens mounted therein, wherein the cylindrical lens is positioned between the linear array of light-emitting elements and the aperture, a length of each of the linear array of light-emitting elements, the aperture, and the cylindrical lens are symmetrically aligned about a longitudinal plane, the aperture spans the length of the cylindrical lens and the length of the light-emitting elements, and is positioned directly adjacent to an emitting face of the cylindrical lens, and light emitted from the linear array of light-emitting elements and passing through the cylindrical lens is emitted from the emitting face and focused by the aperture within a beam width centered about the longitudinal plane.
In this manner, the technical result of emitting narrow beam width radiation for edge-curing a work piece comprising a narrow beam width target region while reducing over curing of the work piece outside of the narrow width region may be achieved. Furthermore, in some embodiments, the aperture may be removably mounted to the housing, thereby facilitating retrofitting of existing lighting devices. Further still, removably mounting the aperture to the housing can enable adjustment of the aperture size of the edge-curing device, making the edge-curing device more flexibly adaptable to various edge-curing applications.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.